LIQUID-CRYSTAL COMPOUNDS HAVING LARGE VALUE OF PERMITTIVITY ANISOTROPY, LIQUID-CRYSTAL COMPOSITION CONTAINING THE SAME, AND LIQUID-CRYSTAL DISPLAY ELEMENT MADE USING THE LIQUID-CRYSTAL COMPOSITION

摘要

Provided are liquid crystalline compounds having an extremely large dielectric anisotropy value, liquid crystal compositions comprising the compound and having a low driving voltage, and liquid crystal display devices fabricated by using the liquid crystal composition; and the liquid crystalline compounds are expressed by the general formula (1) <CHEM> wherein Ra represents a straight chain or branched alkyl group having 1 to 20 carbon atoms; Rb represents a group selected from Ra, a halogen atom, or cyano group; Rc and Rd each independently represent hydrogen atom or an alkyl group having 1 to 3 carbon atoms; A1, A2, A3, and A4 each independently represent pyridine oxide, pyrimidine dioxide, trans-1,4-cyclohexylene, or 1,4-phenylene provided that at least one of A1, A2, A3, and A4 is pyridine oxide ring or pyrimidine dioxide ring; Re represents hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms; Z1, Z2, and Z3 each independently represent single bond or an alkylene group having 1 to 4 carbon atoms one or more hydrogen atoms in which group may be replaced by halogen atoms; m, n, and p are each independently 0 or 1 provided that p is 0 when A4 is pyridine oxide ring bonded, at its position 4, to Z3; and the atom which constitutes these compounds may be replaced by its isotope.